The primary purpose of this study is to examine the impact of oral structure deficits on phonologic systems and articulatory skills. Forty-eight children with unilateral cleft palates and 24 non-cleft matched control subjects will be followed at three-month intervals between the ages of three months and three years. A wide range of speech and language measures will be determined from audio and video recordings of the children's verbal output. The speech samples will be analyzed as to prelinguistic and linguistic productions. To factor-in the influence of the timing of palatal repair surgery, two subgroups of children with cleft palate will participate. One subgroup will undergo surgery prior to the onset of meaningful speech, approximately at the age of 12 months, while the other one will undergo surgery after the onset of such speech, approximately at the age of 18 months. The secondary purpose is to examine the role of parental feedback on children's development of compensatory articulations. Parents will be asked to teach words containing sounds not present in the child's phonetic inventory that have the potential for being produced with compensatory articulation. The type of feedback employed by mothers whose children subsequently develop compensatory articulations will be compared to feedback employed by mothers whose children do not develop these maladaptive behaviors.